1. Field of the Invention
This invention relates to a small-sized electronic appliance that the connection can be stabilized from a sensor unit to a circuit board.
2. Description of the Prior Art
FIG. 6 is a partial sectional view showing an electronic timepiece with a sensor disclosed in Japanese Patent Laid-open No. 339294/1992. In this electronic timepiece with a sensor 500, a circuit board 502 is provided on a housing 501 made of a synthetic resin. On this circuit board 502 a flexible connection board 503 is provided, and this connection board 503 is connected to a sensor unit (not shown). Meanwhile, the connection board 503 is urged onto the circuit board 502 by a support member 504. The support member 504 is fixed on the housing 501 by a screw 505, a thread portion of which is screwed to a clip 506 provided in the housing 501. Also, a spacer 507 of an elastic member is provided between the support member 504 and the connection board 503. The spacer 507 has a projection 571 formed in an underside, and this projection 571 is to be abutted against the connection board 503. An electronic part 508, such as a temperature compensation resistance, is attached on the connection board 503 in the support member 504. In this electronic timepiece with a sensor 500, the connection board 503 is urged onto the circuit board 502 by an elastic force obtained due to tightening of the spacer 507 and screw 505, thereby securing electrical conduction.
In the conventional electronic timepiece with a sensor 500, however, because screw fixing is made to the synthetic resin-made housing 501, the screw 505 readily loosen due to deformation by thermal expansion or external stresses. Also, there is a fear that the urging force of the connection board 503 and circuit board 502 weakens due to deterioration in the spacer 507. Due to this, there has been a problem that a contact state worsens between the connection board 503 and the circuit board 502. In particular, such problem has a great affection for a small-sized electronic appliance because a current to be used is slight.
Besides this, the examples for connecting the sensor unit and circuit board include a wrist watch with a sensor disclosed in Japanese Patent Laid-open No. 270551/1995. FIG. 7 is a partial sectional view showing this wrist watch with a sensor. This wrist watch with a sensor 600 provides direct electrical conduction between the sensor unit 601 and the circuit board 602 without using a flexible connection board. The sensor unit 601 is attached to a case 603 and supported by a sensor retaining part 604. The sensor unit 601 is electrically connected through the circuit board 602 provided on a backside of a panel frame 605 and a connector 606. A cell 608 is accommodated in a space between the circuit board 602 and a back lid 607.
However, in this wrist watch with a sensor 600 there is a restriction in design concerning the sensor position in comparison to the above electronic timepiece with a sensor 500 in that no flexible connection board is used. Furthermore, because the principal object is not in an improvement of a connection state of the circuit board 602 and sensor unit 601, devising seems to be not made in the relevant portion (around connector). Due to this, there is a possibility that poor contact occur between the circuit board 602 and the connector 606 during manufacture, cell exchange or the like.
Therefore, this invention has been made in view of the above and its object is to provide a small-sized electronic appliance with a sensor that an electric connection can be stabilized from a sensor unit to a circuit board.